Procedure

If you select the **Custom404** option, you need to store the page resources, like other static files, under the origin site domain.You can access the page through a CDN domain by entering the complete URL (including `http://`) of the CDN domain.

For example,if the CDN domain is`exp.aliyun.com`and the 404 page is`error404.html`, you can store the `error404.html` page to the origin site.Select the **Custom404** option,and enter `http://exp.aliyun.com/error404.html`.